WHiTEAVES.] LARAJIIE AND CRETACEOUS INVERTEBRATA. .)'.} 



Nebrascana, the Crenella parvula here described, and an undescribed 

 gasteropod belonging apparently to the genus Apoirhais or Anchura. 



On the other hand, at each of the localities at which these fossils 

 were collected they are invariably and directly associated with numer- 

 ous examples of one or more species of Uniu, and at the South Sas- 

 katchewan and near Bull's Head with large Phys"'. All the specimens 

 of the present shell, too, which Mr. McConnell obtained at the South 

 Saskatchewan in 1883, and which have most of the inner layer of the 

 test jjreserved, are brilliantly nacreous, and young individuals, from 

 more than one Canadian locality, are remarkably like Dr. White's 

 figures of the young of A. propatoris. 



Unio prim-Evus, White. 



XJnio pi-ima:r>i<^ White. 1S77. Bull. U. S. Geol. Surv. Terr., vol. III., p. 599. 

 " •' "White. IbSO. U. S. Geol. Surv., Contr. to Pal., Xos. ■!-?,, p. 70, 



pi. 29, figs. 3a and b. 



White. 1883. Rev. Xon-Marine Foss. Moll. X. Am., p. 26, pi. 14, 

 tigs. 4 and .5. 



Branch of Ea^t Fork of Milk Eiver, Township 1, Eange 27, west of 

 3rd Principal Meridian, E. G. McConnell, 1SS3 : one specimen with 

 both valves, but with most of the outer layer of the test exfoliated. 



Unio Dan-E, Meek and Hayden. 



r-alo /).m;., Meek and Hayden. 1857. Proc. Ac. Xat. Sr., Phil., vol. IX, p. 145. 



" •' 3Ieek. 1876. Rep. U.S. Geol. Surv. Terr., \o\. IX., Rep. luv. Cret. 



and Tert. Foss. U. Miss. Cy., p. 517, pi. 41, figs. 3, a, b, c. 



South Shore of the Belly Eiver above Coal Banks, T. C. Weston, 

 1883 : four specimens, which are very variable in form. 



Unio consuetus. (X. Sp. ?) 



Plate 9, figs. 4 and 4 a. 



Shell rather large, moderately convex, ( the maximum thickness 

 through the closed valves as compared with their height being about 

 as three to five) transversely elongated, a little more than twice as 

 long as high, very inequilateral, the anterior side being extremely short, 

 and the posterior much produced ; superior and inferior borders very 



